The SHA-256d Hash for Go

By Jochen Voss, last updated 2013-07-16

The sha256d package provides an implementation of the SHA-256d hash algorithm (also known as "double SHA-256") for the Go programming language. SHA-256d is a cryptographic hash, first proposed by Ferguson and Schneier in the book "Practical Cryptography". The SHA-256d hash is used in the Bitcoin protocol and in the Fortuna random number generator.

The SHA-256d hash is obtained by applying the SHA-256 hash twice, i.e. by first applying SHA-256 to the data and then again to the resulting hash.


To download the sha256d package, simply use the go get command as follows:

  go get

The source code is available at


The sha256d package implements the standard hash.Hash interface. Example:

  hash := sha256d.New()
  n, _ := hash.Write([]byte("hello"))
  hashVal := hash.Sum(nil)

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